Extrusion International 1-2021

33 Extrusion International 1/2021 MAS Maschinen- und Anlagen Schulz GmbH A-4055 Pucking, Austria Juergen Morosz – MAS -Area Sales Manager E-j.morosz@mas-austria.com www.mas-austria.com Based on the co-rotating screws, the conical MAS-extrud- ers offer a speci fi c property pro fi le that makes them ideal for complex recycling and compounding tasks. Outstand- ing is the very uniform plasticization at a comparatively low to medium pressure and shear level, documented by measurements of the physical product characteristics. Their analysis show that the qualities of the input material stay at maximum after processing which is of decisive im- portance for both recycling applications and compounding tasks. Thanks to their modular structure, the screws can be easily and quickly fi ne-tuned to a speci fi c task by exchang- ing individual screw-segments. Another advantage is the system-speci fi c large feed open- ing on the extruder, which favors the feeding in of material with a low bulk density, such as recycling fl akes or fi brous and powdery additives in compounding technology. MAS-ES compounder for multi-stage melt cleaning by means of degassing High up on the Pan Era Group’s project speci fi cation was the ability to produce in an one-stage-process a particle- free HDPE in different colors, suitable for producing new high quality packaging fi lms or various bottles for deter- gents or other household chemicals. The area salesmanager ofMAS, JuergenMorosz comments: “The challenge was to correctly assess the input material in terms of its compositionanddegreeof soilingand the system design required for processing. In close cooperationwith the customer, after a series of representative material tests, we have found a process technology solution that optimally uses the potential of the MAS extruder. The ideal solution was, respectively is, a system concept derived from our ES compounder extruder cascade. It consists of a single-screw extruder for melting and plasticizing the washed and dried PE fl akes and a subsequent CDF 500-D twin disc fi lter unit from our supply program, where particles with a fi neness of 130 μ m are retained and segregated. The thus cleaned material stream is then fed to the conical MAS twin-screw extruder by side-feed- ing in the area of the feed zone. But that was not enough cleaning. There were still printing ink residues and odor emissions in the melt. In order to remove these contaminations we have added a vacuum unit to the speci fi cally large intake opening of the twin-screw-extruder and converted it into a de- gassing zone, where the volatile melt components can be sucked off ef fi ciently. From there thepolymermelt is conveyed further, compressedgen- tly and homogenized until it fi nally reaches a second degas- sing zone for second cleansing (Picture 5). Passing an MFI- measuring station, it fi nally reaches the granulating unit.” As an additional bonus, the system concept also offers the compounding ability which actually is used to achieve high degree of homogenization of the recycled resin. As it is the core property of the ES-compounder systems, there is the in- tention to use it for extending the scope of materials to com- pounded materials for technical applications. To do this, the feed zone of the MAS twin screw extruder only needs to be combined with a vacuum lock through which powdered ad- ditives such as talc or calcium carbonate can be added with- out the need for additional side feeder units. Thismeans that Pan Era Group has every opportunity to expand the r-HDPE range to include material variants for technical applications. Author: Reinhard Bauer - TECHNOKOMM of f i ce@technokomm.at Picture 3: General view of the Pan-Era production of fi lmpackaging-bags (Photo: Pan-Era) Picture 4: Examples of product of Pan Era Groupmade from at least 80% r-HDPE (Photo: Pan Era) Picture 5: TheMAS recycling plant is the combination of a single-screw extruder for plasticizing the pre-cleaned PE- fl akes (left) and a twin-screw extruder for ef fi cient degassing and the potential for up-cycling through compounding with additives (Photo: MAS)